Composite structures often include a laminate structure in which sheets of a composite material, such as a prepreg material, may be bent, wrapped, and/or otherwise extended between a first plane, or surface, and a second plane, or surface. The finite thickness and mechanical stiffness of the sheets of composite material result in a finite bend, or radius of curvature, in a transition region between the first surface and the second surface and, in some geometries, this finite radius of curvature results in a void space, or cavity, between adjacent sheets of composite material.
Generally, this void space is filled with, or otherwise occupied by, a filler material, such as a radius filler. The radius filler may be configured to provide mechanical support to the sheets of composite material that are proximal thereto and/or decrease a potential for distortion of the sheets of composite material while the composite structure is curing. While the presence of the radius filler may provide a variety of benefits to the composite structure, differences between a geometry, cross-sectional shape, or transverse cross-sectional shape of the radius filler when compared to a geometry, cross-sectional shape, or transverse cross-sectional shape of the void space may distort the composite structure during formation and/or curing of the composite structure. Thus, it may be desirable to closely match the shape of the radius filler to a shape, or a desired shape, of the void space. In addition, it also may be desirable to match the mechanical properties of the radius filler to that of the sheets of composite material and/or the resultant composite structure, thereby improving the overall durability of the composite structure.
Traditional systems and methods for radius filler construction are highly labor intensive, are batch processes, require the use of jigs that are as long as the radius filler that is to be produced and thus utilize a large amount of floor space, do not produce a radius filler with a geometry that is well matched to the geometry of the void space, do not provide for control of the mechanical stiffness of the radius filler, and/or are inherently wasteful and produce a significant amount of scrap material. As composite structures become larger and more complex, these limitations become increasingly significant, increasing the costs associated with composite structure construction. As an illustrative, non-exclusive example, next-generation aircraft may utilize composite structures that are approximately 10 meters in diameter, 33 meters long, and include 1000 or more lengths of radius filler, which also may be referred to herein as noodles. Thus, there exists a need for improved radius fillers for composite structures, as well as for improved systems and methods for fabricating the radius fillers.